Amusements in Mathematics
was also present. The favourite method is to take eight counters or pieces of cardboard
and mark them A, B, C, D, a, b, c, d, to represent the four men and their prospective
brides, and carry them from one side of a table to the other in a matchbox (to represent
the boat), a penny being placed in the middle of the table as the island.
Readers are now asked to find the quickest method of getting the party across the river.
How many passages are necessary from land to land? By "land" is understood either
shore or island. Though the boat would not necessarily call at the island every time of
crossing, the possibility of its doing so must be provided for. For example, it would not
do for a man to be alone in the boat (though it were understood that he intended merely to
cross from one bank to the opposite one) if there happened to be a girl alone on the island
other than the one to whom he was engaged.
377.—STEALING THE CASTLE TREASURE.
The ingenious manner in which a box of treasure, consisting principally of jewels and
precious stones, was stolen from Gloomhurst Castle has been handed down as a tradition
in the De Gourney family. The thieves consisted of a man, a youth, and a small boy,
whose only mode of escape with the box of treasure was by means of a high window.
Outside the window was fixed a pulley, over which ran a rope with a basket at each end.
When one basket was on the ground the other was at the window. The rope was so
disposed that the persons in the basket could neither help themselves by means of it nor
receive help from others. In short, the only way the baskets could be used was by placing
a heavier weight in one than in the other.
Now, the man weighed 195 lbs., the youth 105 lbs., the boy 90 lbs., and the box of
treasure 75 lbs. The weight in the descending basket could not exceed that in the other by
more than 15 lbs. without causing a descent so rapid as to be most dangerous to a human
being, though it would not injure the stolen property. Only two persons, or one person
and the treasure, could be placed in the same basket at one time. How did they all manage
to escape and take the box of treasure with them?
The puzzle is to find the shortest way of performing the feat, which in itself is not
difficult. Remember, a person cannot help himself by hanging on to the rope, the only
way being to go down "with a bump," with the weight in the other basket as a